mean.se: Plot the mean and standard error for some data.
In haberdashPI/wright.lab.util: A set of utilitiy functions used in our lab.

TODO

1	mean.se(formula, data, error.col = NULL, error.lwd = NULL, error.lty = 1, error.length = 0.05, ...)

`formula`
`data`
`error.col`
`error.lwd`
`error.lty`
`error.length`
`...`

##---- Should be DIRECTLY executable !! ----
##-- ==>  Define data, use random,
##--	or do  help(data=index)  for the standard data sets.

## The function is currently defined as
function (formula, data, error.col = NULL, error.lwd = NULL, 
    error.lty = 1, error.length = 0.05, ...) 
{
    args = list(...)
    if (hasArg(lwd) && length(error.lwd) == 0) 
        error.lwd = args$lwd
    else if (length(error.lwd) == 0) 
        error.lwd = 1
    if (hasArg(col) && length(error.col) == 0) 
        error.col = args$col
    else if (length(error.col) == 0) 
        error.col = "black"
    means = aggregate(formula, data, mean)
    ses = aggregate(formula, data, std.error)
    last = ncol(means)
    arrows(ses[, 1], means[, last] - ses[, last], ses[, 1], means[, 
        last] + ses[, last], error.length, angle = 90, code = 3, 
        col = error.col, lty = error.lty, lwd = error.lwd)
    lines(means[, 1], means[, last], ...)
  }